//  Sketch by R. Jordan Kreindler, written September 2016, 
//    to rotate a stepper motor using the Wave Drive Method

int aPin      = 2; //IN1: first end of the blue and yellow stator coil
int bPin      = 3; //IN2: first end of the pink and orange stator coil
int aPrimePin = 4; //IN3: second end of the blue and yellow stator coil
int bPrimePin = 5; //IN4: second end of the pink and orange stator coil
// We do not connect IN5, IN6, or IN7

int delay1 = 75;

void setup() {
  // Set all pins as output to send output signals from the Arduino 
  //   UNO to the coil windings of the stator
  pinMode(aPin,      OUTPUT);
  pinMode(bPin,      OUTPUT);
  pinMode(aPrimePin, OUTPUT);
  pinMode(bPrimePin, OUTPUT);   

  // Start with all coils off
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, LOW);
}

void loop() {
  // Send current to the apin, and then the bpin
  //   then reverse the current and send reversed current
  //   to aPrimePin and then bPrimePin. 

  // 1. Energize the blue yellow stator coil
  digitalWrite(aPin,      HIGH);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, LOW);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds
  
  // 2. Energize the blue yellow stator coil
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      HIGH);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, LOW);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds
  
  // 3. Reverse current direction and energize the blue yellow stator coil
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, HIGH);
  digitalWrite(bPrimePin, LOW);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds
  
  // 4. Reverse current direction and energize the pink orange stator coil
  digitalWrite(aPin,      LOW);
  digitalWrite(bPin,      LOW);
  digitalWrite(aPrimePin, LOW);
  digitalWrite(bPrimePin, HIGH);
  // Allow some delay between energizing the coils to allow
  //  the stepper rotor time to respond.
  delay(delay1); // So, delay1 microseconds

}